Garmin mapping GPS units have built in basemaps with major highways, rivers, etc. For street level detail additional software is required. Both the Metro Guide and City Navigator provide detailed maps containing highways, interstates, business and residential roads with attributes such as turn restrictions, speed categories, millions of points of interest (food, lodging, attractions, emergency services etc.) for metropolitan and rural areas of the USA, Canada and Puerto Rico. Metro Guide will calculate routes on the PC only while City Navigator will calculate routes on compatible GPS units as well. Both allow for the transfer of waypoints routes, and tracks between your Garmin GPS and your PC.
U.S. Topo CD: Download topographic detail to your compatible GPS. You'll see terrain contour, elevation information, shoreline detail, bathymetric contours, hiking and snowmobile trails and more. You can also create routes and waypoints on your PC and transfer them to your GPS.
WorldMap provides worldwide coverage with basemap-level detail including: political boundaries, cities, towns, major motorways and/or interstates, and principal highways; lakes, major streams, and rivers; and urban areas and railroads, coastline detail which includes many offshore islands, as well as worldwide nautical navaids, and U.S. Interstate Exits information, such as service stations, gas stations, restaurants, hotels, campsites, hospitals, banks. Includes trip and waypoint management functions